Abstract: A synthetic jet actuator and a method for optimizing a synthetic jet actuator to meet operating requirements and physical constraints may include estimating dimension and a resonance frequency of an air cavity of the synthetic jet actuator, and using the estimated resonance frequency to the estimate dimensions of a piezoelectric actuator of the synthetic jet actuator. Individual simulations of the air cavity and piezoelectric actuator, and a coupled simulation may be performed using the estimated dimensions, and the dimensions may be revised and simulations re-executed to match the resonance frequencies of the air chamber and the piezoelectric actuator. The method maybe yield a synthetic jet actuator having a resonance frequency of the piezoelectric actuator that is approximately equal to a quarter-wavelength resonance frequency of the air cavity.

Abstract: Described are methods and systems for broad-band active reduction of noise in target spaces, such as spaces around headrests in aircraft cabins. Systems describe herein are effective over wide frequency ranges without causing undesirable amplification at any subrange ranges. Specifically, a system comprises a speaker and a resonator, both coupled to an enclosure. The interior space of the resonator is in fluid communication with the enclosed space of the enclosure, allowing the resonator to reduce the amplitude of unwanted amplification by the audio reducing sound generated by the speaker. The amplitude is reduced in a selected frequency range, which may correspond to an expected amplification for this particular system. The resonator may partially extend into the enclosure or may be completely incorporated into the enclosure. Some examples of the resonator include a Helmholtz resonator, a passive radiator, a quarter wave resonator, a pipe resonator, and an acoustic metamaterial.

Abstract: Methods of damping vibrations in a host structure are described. In one embodiment, the vibrations can be damped using a tuned mass damper. The tuned mass damper can include a suspended mass with magnets which is configured to move in response to current being applied to a voice coil. The tuned mass damper can damp vibrations resulting from an external load applied to the host structure, such as an external aerodynamic load. In one embodiment, the tuned mass damper can be mounted within a wind tunnel model undergoing transonic testing. The tuned mass damper can be operated to limit potentially destructive vibrations which can occur during testing.

Abstract: An active flow control drag-induced damping reduction apparatus. The apparatus includes a variable frequency signal power supply; a jet generator defining an internal cavity and having pump member, and coupled to the variable frequency signal power supply to receive a control signal; a feedback sensor coupled to the pump member to generate a feedback signal measuring the reciprocating motion of the pump member; a detection circuit that receives the feedback signal and measures a difference compared to the variable frequency generator; and an adjustment circuit that receives the measured difference and tunes the variable frequency signal of the variable frequency signal power supply to maintain the jet generator at an optimum flow.

Abstract: Described are methods and systems for broad-band active reduction of noise in target spaces, such as spaces around headrests in aircraft cabins. Systems describe herein are effective over wide frequency ranges without causing undesirable amplification at any subrange ranges. Specifically, a system comprises a speaker and a resonator, both coupled to an enclosure. The interior space of the resonator is in fluid communication with the enclosed space of the enclosure, allowing the resonator to reduce the amplitude of unwanted amplification by the audio reducing sound generated by the speaker. The amplitude is reduced in a selected frequency range, which may correspond to an expected amplification for this particular system. The resonator may partially extend into the enclosure or may be completely incorporated into the enclosure. Some examples of the resonator include a Helmholtz resonator, a passive radiator, a quarter wave resonator, a pipe resonator, and an acoustic metamaterial.

Abstract: A modular interferometric telescope including a base and an optical detector. A mounting beam has a first end, a second end, and a length, and is connected rotatably to the base at a point between the first and second end. The mounting beam is rotatable about a first axis extending in a direction of an object to be observed. A first light-collecting assembly is connected to the mounting beam proximal to the first end relative to the second end. The first light-collecting assembly directs light from the object to the optical detector. A second light-collecting assembly connected to the mounting beam is proximal to the second end relative to the first end. The second light-collecting assembly directs the light from the object to the optical detector. A first optical assembly is configured to receive the light from the object and direct the light to the optical detector.

Abstract: Systems and methods for dampening dynamic loading between two bodies are described. An example dampening system includes a non-ferrous metal body attached to a second body and a stack of magnets attached to a third body. The stack of magnets is movably disposed within or around the non-ferrous metal body, and adjacent magnets are arranged in an opposed polar relationship, whereby relative movement of said second and third bodies is damped. An example method of dampening dynamic loading includes arranging a plurality of magnets along an axis to form at least one pair of magnets having an opposed polar relationship along the axis. The method further includes axially moving the at least one pair of magnets relative to a non-ferrous metal body, so as to dampen dynamic loading of a payload attached to a vehicle.

Abstract: Systems and methods for dampening dynamic loading between two bodies are described. An example dampening system includes a non-ferrous metal body attached to a second body and a stack of magnets attached to a third body. The stack of magnets is movably disposed within or around the non-ferrous metal body, and adjacent magnets are arranged in an opposed polar relationship, whereby relative movement of said second and third bodies is damped. An example method of dampening dynamic loading includes arranging a plurality of magnets along an axis to form at least one pair of magnets having an opposed polar relationship along the axis. The method further includes axially moving the at least one pair of magnets relative to a non-ferrous metal body, so as to dampen dynamic loading of a payload attached to a vehicle.

Abstract: Methods of damping vibrations in a host structure are described. In one embodiment, the vibrations can be damped using a tuned mass damper. The tuned mass damper can include a suspended mass with magnets which is configured to move in response to current being applied to a voice coil. The tuned mass damper can damp vibrations resulting from an external load applied to the host structure, such as an external aerodynamic load. In one embodiment, the tuned mass damper can be mounted within a wind tunnel model undergoing transonic testing. The tuned mass damper can be operated to limit potentially destructive vibrations which can occur during testing.

Abstract: An acoustic cavity tailored synthetic jet employs a body having a cavity with a wall including a taper from a first extent to an aperture. The cavity is configured to produce a matched acoustic resonance. A drive system has a piston engaged to the cavity at the first extent. The drive system and piston are configured for oscillatory motion inducing a synthetic jet at the aperture.

Abstract: A strain amplification structure has a frame with a hexagonal structure incorporating a plurality of rigid beams that are connected to opposing end beams by a plurality of flexible joints. A piezoceramic actuator assembly is connected to the opposing end beams having a collar including an opening. A shaft providing an output is connected to the plurality of rigid beams with flexible joints and passes through the opening in the collar for non-interfering motion orthogonal to the actuator assembly.

Abstract: An aperture partitioning element for an imaging system is disclosed. The aperture partitioning element includes a plurality of segments each including a reflective surface and a body. The plurality of segments are each independently moveable in at least one of an x-axis, a y-axis, and a z-axis of the aperture partitioning element. The aperture partitioning element also includes at least one positioner received within the body of a corresponding segment. The at least one positioner is actuated to move the corresponding segment in at least one of the x-axis, the y-axis, and the z-axis.

Abstract: A synthetic jet actuator and a method for optimizing a synthetic jet actuator to meet operating requirements and physical constraints may include estimating dimension and a resonance frequency of an air cavity of the synthetic jet actuator, and using the estimated resonance frequency to the estimate dimensions of a piezoelectric actuator of the synthetic jet actuator. Individual simulations of the air cavity and piezoelectric actuator, and a coupled simulation may be performed using the estimated dimensions, and the dimensions may be revised and simulations re-executed to match the resonance frequencies of the air chamber and the piezoelectric actuator. The method maybe yield a synthetic jet actuator having a resonance frequency of the piezoelectric actuator that is approximately equal to a quarter-wavelength resonance frequency of the air cavity.

Abstract: A synthetic jet actuator and a method for optimizing a synthetic jet actuator to meet operating requirements and physical constraints may include estimating dimension and a resonance frequency of an air cavity of the synthetic jet actuator, and using the estimated resonance frequency to the estimate dimensions of a piezoelectric actuator of the synthetic jet actuator. Individual simulations of the air cavity and piezoelectric actuator, and a coupled simulation may be performed using the estimated dimensions, and the dimensions may be revised and simulations re-executed to match the resonance frequencies of the air chamber and the piezoelectric actuator. The method maybe yield a synthetic jet actuator having a resonance frequency of the piezoelectric actuator that is approximately equal to a quarter-wavelength resonance frequency of the air cavity.

Abstract: A synthetic vacuum generator has a case enclosing an interior cavity with an aperture through the case in communication with the cavity. A piston and a check valve are mounted in the case in fluid communication with the cavity and the aperture. The piston and check valve are configured with symbiotic resonant response to establish an outflow there through and inducing an inflow through the aperture upon reciprocation of the piston at a predetermined frequency.

Abstract: A vehicle may include an operative sub-system positioned within a body of the vehicle, and a sensor assembly secured to the operative sub-system. The sensor assembly may include at least one sensor configured to detect vibration or shock energy, directed into the operative sub-system; and a processing unit configured to determine damage to the operative sub-system as damage data that is based on one or both of a magnitude and duration of the vibration or shock energy detected by the sensor(s). The sensor assembly may be self-powered.

Abstract: A tunable mass damper incorporates a frame and a voice coil supported in the frame. A magnet concentric with the voice coil is movable relative to the housing via the voice coil. A plurality of flexures having a first end extending from the magnet and an arm releasably coupled to the frame are adjustable to an effective length for a desired frequency of reciprocation of the magnet.

Abstract: A method and apparatus for identifying a position of a deployable system. An apparatus comprises a sensor device. The sensor device comprises a sensor configured to detect at least one of first vibrations from a deployable system in a first position or second vibrations from the deployable system in a second position in which the first vibrations are different from the second vibrations. The sensor is further configured to generate information from detecting at least one of the first vibrations or the second vibrations.

Abstract: A tunable mass damper incorporates a frame and a voice coil supported in the frame. A magnet concentric with the voice coil is movable relative to the housing via the voice coil. A plurality of flexures having a first end extending from the magnet and an arm releasably coupled to the frame are adjustable to an effective length for a desired frequency of reciprocation of the magnet.

Abstract: An active flow control drag-induced damping reduction apparatus. The apparatus includes a variable frequency signal power supply; a jet generator defining an internal cavity and having pump member, and coupled to the variable frequency signal power supply to receive a control signal; a feedback sensor coupled to the pump member to generate a feedback signal measuring the reciprocating motion of the pump member; a detection circuit that receives the feedback signal and measures a difference compared to the variable frequency generator; and an adjustment circuit that receives the measured difference and tunes the variable frequency signal of the variable frequency signal power supply to maintain the jet generator at an optimum flow.